Smart Antennas Drive Evolution in M2M and Automotive Applications
Smart antennas provide the capability to co-locate the antenna and black-box functionality for better performance and lower cost.
The power of machine-to-machine (M2M) technology is driving towards a more connected world. All kinds of machines are getting connected to the Internet of Things to deliver the promise of enhanced productivity and to bolster the performance of businesses.
The evolving realms of technology are revolutionizing many industries. The automotive industry is trending towards intelligent cars that are fully connected in order to achieve vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2I) communication for improved safety. Fleet management companies are utilizing M2M systems to monitor operational performance and service efficiency using real-time fleet tracking. Smart technology is enabling improved supply chain systems in industries such as vending and service.
Reliable non-stop connectivity requires that these systems support a wide array of wireless capability. This means machines are getting packed with Bluetooth, Bluetooth Low Energy (BLE) and Wi-Fi for personal or local network connection; Cellular protocols such as 2G, 3G, 4G and LTE for wide-area network connection; and global navigation satellite systems (GNSS) such as GPS, Galileo, Glonass and Beidou to support location-based services. This demand for added capability pushes toward higher system-level sophistication which can create challenges.
Challenges of Traditional M2M Systems
Traditionally, embedded M2M systems come with a black box containing connectivity features, control circuitry, power supply circuitry, wireless radios and other functions. The black box then connects to the bus system and/or a power source within the machine to allow the M2M system to run. Many connected machines in the field are metallic (examples include vehicles, vending machines, generators and containers). On these metallic structures, the antenna for the M2M system must be installed on the outside of the machine to maximize the system performance. As such, the antennas for the M2M system are in a different physical location than the black box and are connected to the black box via RF cables (as seen in Figure 1).
|Figure 1: Vending machine in a traditional M2M system|
Even though this architecture is used on many M2M systems, it poses several potential system concerns. First, RF cables inherently have loss; the longer the cable, the more antenna gain lost between the black box and the antenna negatively affecting system performance. Second, there are two cost implications. Running multiple RF cables increases the total cost of the system, especially if the distance between the black box and the antenna is large. Additionally, as more technology gets added to the M2M system, more cables need to be run, which also adds cost and complexity. Finally, with more cables and more connectors within the system there are increased installation costs and higher risk of intermittent connection failures. For example, in heavy equipment and automobiles that are prone to vibration, there could be higher instances of connector or cable damage resulting in loss of data.
Smart Antennas Maximize Efficiency, Minimize Cost
One way to reduce system cost and improve efficiency in embedded M2M applications is to re-think the architecture of an embedded M2M system. Instead of depending on the black box to perform all of the critical tasks of the system, a system designer could pull the wireless portion of the design in to the antenna. This concept can be referred to as a smart antenna design.
|Figure 2: Smart antenna architecture for vehicle|
Smart antennas provide an option to co-locate the antenna and some of the black box device functionality (mainly radios) into the antenna package. A single digital cable can then be run from the smart antenna to the depopulated black box. See Figure 2 for an example of how a smart antenna could be architected to work in a vehicle environment.
The embedded M2M system then becomes more efficient as the loss of data between the antenna and the black box is minimized with a digital cable versus multiple coaxial cables. Digital signals can utilize error-correction software and are more resistant to electromagnetic noise and signal attenuation than analog signals. Additionally, cellular systems are evolving quickly and other wireless standards continue to get updated. Customers not only want to upgrade their systems from 2G to 3G and 4G but also want to add the most cutting-edge wireless functionality (i.e., BLE and Wi-Fi Direct). When the technology evolves, it drives hardware and software changes. These hardware and software changes then need to be re-validated and re-certified. By moving the wireless functionality into the antenna, the core black box no longer needs to evolve as quickly as the wireless market pushes. The smart antenna can truly act as the data pipe and the black box can focus on its key functionality.
|Figure 3: Example of smart antenna for vending machine|
Finding the Right Fit
While a number of market players provide smart antenna solutions, not all of them are successfully able to address all of the challenges. Getting the design right is the first step.
Because the smart antenna packages additional components into the antenna, the size of the smart antenna may be larger than a regular antenna. Space and styling constraints on certain equipment will not allow larger smart antenna packages than typical antenna sizes. For instance, the styling of a vehicle is very important to vehicle OEMs. It is critical that the smart antenna is created with the customer’s or system integrator’s guidelines in mind.
Depending upon where the smart antenna is located on the subject equipment, there could be more stringent environmental challenges. Electronics that were once hidden inside of the equipment are now located outside of the equipment in the antenna package This may create additional challenges with temperature, humidity, water ingress or a variety of other environmental factors.
Moving the radios from the black box into the antenna could pose firmware challenges. Typically the black box has been seen as the brain of the system with the antenna being the afterthought. When moving some of the electronics away from the black box to the antenna, it is critical to understand how information will be passed from the smart antenna to the black box. No longer is there just an RF signal coming from the antenna. Depending on the complexity of the smart antenna design, there could be RF data, location data and machine bus information passing over a digital line. In this case, there will be some firmware required within the smart antenna. If these issues are not addressed correctly during the system design phase, persuading system integrators to adopt smart antenna architecture will be a challenge.
Although challenges exist, the adoption of smart antenna technology in to the embedded M2M system space could lead to more efficient systems for companies looking to maximize performance while controlling initial capital expense and long term system evolution costs.
Jason Furr is global sales manager for Laird, where he focuses on generating new business in the growing telematics & M2M markets. Jason holds a bachelor’s degree in business from The University of Michigan-Dearborn and an MBA from Michigan State University.
Vidhya Dharmarajan is a technical writer for Laird, where she is responsible for creating, refining and maintaining product documents and writing white papers, market research and competitor analysis for the Telematics business group. Vidhya holds a master’s degree in VLSI Design from San Jose State University in California.